file uploading in codeIgniter (After selecting a file and click upload, being directed to XAMP home page)

Code:
hi im new to codeIgniter n have a problem while using the file upload script from user  

guide, upload form view is executing and displays the output, but after selecting a  

file and click on upload its being directed to XAMP home page as im using XAMP, [quote]Any  

help is greatly appreciated.[/quote]

/*this is view code I used upload_form.php code*/  

&lt;html&gt;  

&lt;head&gt;  

&lt;title&gt;Upload Form&lt;/title&gt;  

&lt;/head&gt;  

&lt;body&gt;    



&lt;?php echo $error;?&gt;  



&lt;?php echo form_open_multipart('upload/do_upload');?&gt;  



&lt;input type="file" name="file" /&gt;  



<br /><br />  



&lt;input type="submit" value="upload" /&gt;  



&lt;/form&gt;  



&lt;/body&gt;  

&lt;/html&gt;  





 /*this is the controller class I used upload.php code*/  

&lt;?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');  





class Upload extends CI_Controller  

{  

function _construct()  

{  

    parent::_construct();  

    $this->load->helper(array('form','url','file'));  

}  

function index()  



{  

    $this->load->view('upload_form', array('error' => ' ' ));  

}  



function do_upload()  

{  

    $config['upload_path'] = $_SERVER['DOCUMENT_ROOT']."uploads";  

    $config['allowed_types'] = 'gif|jpg|png';  

    $config['max_size']= '100';  

    $config['max_width']  = '1024';  

    $config['max_height']  = '768';  



    $this->load->library('upload', $config);/* load library file with specified  

                                                       configuration*/    

    $field_name = "file"; /*variable passed to form*/   



    if (!$this->upload->do_upload($field_name))  

    {  

        $error = array('error' => $this->upload->display_errors());  



        $this->load->view('upload_form', $error);  

    }  

    else  

    {  

        $data = array('upload_data' => $this->upload->data());  



        $this->load->view('upload_success', $data);  

    }  

 }  

   }  

?&gt;